Rias Gremory

Rias Gremory is the main female protagonist of High School DxD. She is the next heiress of the Gremory Clan after her older brother Sirzechs took the title of Lucifer. She is the only daughter and youngest child of Zeoticus and Venelana Gremory, the auntie of Millicas Gremory, and the cousin of Sairaorg and Madgaran Bael. She is known as the Crimson-Haired Ruin Princess. She is a first-year college student at Kuoh Academy, the former President of the Occult Research Club, and the school's number-one beauty as well as one of Kuoh Academy's Two Great Ladies alongside Akeno Himejima.

Personality
Rias is a very kind and compassionate individual especially to her servants and people close to her. She also dislikes cruelty towards people as shown with her disgust over Marius Tepes, who abused his own sister for his own benefit, and how she killed the Fallen Angels such as Mittelt, Dohnaseek, Kalawarner, and Raynare for their cruel treatment of Issei. She thinks of Issei as a special person, and always gets jealous when girls are around him, becoming a totally different person when she sees him and other girls together, or when it comes to training. Despite her mature stature like a woman, Rias tends to act her true age and become frustrated whenever girls flirt with Issei. She is proud of her family's name, but she does not like being seen as Rias of the Gremory Family. The reason for her living in the human world (as revealed in Volume 2 of the novels) is because there, everyone sees her as Rias, not as a Devil or as the Crimson-Haired Ruin Princess. Despite being seductive like Akeno, both of the girls are still innocent to love, as both of them become their age whenever around Issei or on a date with him.

She enjoys teasing Issei and Asia (from Volume 3 of the novels onward), but at the same time makes it clear (to Asia or any girl) that Issei is hers, and she does not want to share him at all (It is revealed in Volume 3 of the novels that the Gremory Family and their servants are beings with extraordinary affection among the Devils, so Rias is no exception). She has no problem with showing Issei her breasts or sleeping naked with him (which she always does according to her and she claims she can't sleep without being nude or without Issei).

After becoming Issei's girlfriend, Rias begins to show more confidence in her relationship with Issei and is no longer jealous or angry when Issei is with other girls like she previously was, even accepting Issei's dream of having a harem and letting the girls have dates with him. However, Rias still shows some signs of jealousy such as when Issei doesn't spend enough time with her, but still believes in him and loves him. Like Akeno, Rias shows a sign of dependence toward Issei (possibly lesser than the former) as Rias will lose her will to fight and lead.

She holds her older brother Sirzechs in high regard (despite her older brother's antics of being a siscon) because she deeply cares for him. When she was a child, she was entirely dependant on him and held him in admiration, while also feeling inferior to him at the same time.